Performance, Reliability and Validation of Mass Spring Systems by Means of Vibration-based Excitation Sources

Abstract

This paper presents the experimental evaluation of insertion loss of mounted track systems. Research outcomes can be implemented for the performance monitoring of metro lines and of high-speed railway infrastructures. Measurement-based identification of the systems has been developed following the “left and right test procedure” according to DIN SPEC 45673-3 on three mockups under loaded and unloaded conditions. The mock-up represented a standard track, a light mass spring system (LMSS) and a heavy mass spring system (HMSS) of a metro line. An impact hammer with mass of 8.0 kg capable of exciting a maximum force of 22.5 kN is used as excitation source and nine vibration receivers are used according to several protocols. Time, frequency and time-frequency analysis of all the collected data is presented. Advanced signal processing coupled with filtering techniques has been applied to guarantee the reliability of the data. Scope of the tests is the determination of ground transfer and of natural frequency of loaded and unloaded tracks in order to calculate the characteristic insertion loss. Ground correction curves for the LMSS and the HMSS system are computed and implemented for the final results. Environmental and operational effects are also considered to properly prognose and manage the performance and reliability of the systems. Theoretical insertion loss curves for the HMSS and LMSS systems have been computed according to a 2D 6-degree of freedom numerical model and compared to experimental ones. In all cases, the experimental values are higher than theoretical ones.